E300 Installation and Commissioning Guide
11
Issue Number: 1
2.4.1 Typical short term overload limits
The maximum overload limit changes depending on the selected motor. Variations in motor rated current, motor power factor and motor leakage
inductance all result in changes in the maximum possible overload due to the thermal models estimation of the motor temperature as a percentage of
its maximum allowed temperature. Typical values for overload are shown in the table below:
Table 2-3 Typical overload limits
2.5 Operating modes
The
E300 Advanced Elevator
drive is designed to operate in any of the following modes with the default operating mode being RFC-S
Open loop mode
Open loop vector mode
Fixed V/F mode (V/Hz)
RFC - A, Closed loop vector
With position feedback sensor
Sensorless mode without position feedback for rescue operation
RFC - S, Closed loop Servo
With position feedback sensor
Sensorless mode without position feedback for rescue operation
2.5.1 Open loop mode
The drive applies power to the motor at frequencies varied by the user. The motor speed is a result of the output frequency of the drive and slip due
to the mechanical load. The drive can improve the speed control of the motor by applying slip compensation. The performance at low speed depends
on whether Fixed V/F mode or Open loop vector mode is selected.
Vector mode
The voltage applied to the motor is directly proportional to the frequency except at low speed where the drive uses motor parameters to apply the
correct voltage to keep the flux constant under varying load conditions. Typically 100 % torque is available down to 1 Hz for a 50 Hz motor.
Fixed V/F mode
The voltage applied to the motor is directly proportional to the frequency except at low speed where a voltage boost is provided which is set by the
user. This mode can be used for multi-motor applications. Typically 100 % torque is available down to 4 Hz for a 50 Hz motor.
2.5.2 RFC-A
R
otor
F
lux
C
ontrol for
A
synchronous induction motors
RFC-A
encompasses closed loop vector control with a position feedback device
With position feedback
For use with induction motors with a feedback device installed. The drive directly controls the speed of the motor using the feedback device to ensure
the rotor speed exactly as demanded. Motor flux is accurately controlled at all times to provide full torque all the way down to zero speed.
Sensorless mode without position feedback for rescue operation
Sensorless mode provides closed loop control without the need for position feedback by using current, voltages and key motor parameters to
estimate the motor speed.
Operating mode
Closed loop from cold
Closed loop from 100 %
Open loop from cold
Open loop from 100 %
Heavy Duty overload
Motor rated current = drive rated current
175 % for 40 s
175 % for 5 s
150 % for 60 s
155 % for 8 s
Heavy duty operating mode
The thermal protection is set to protect force ventilated induction motors and permanent magnet servo motors by default. If the application uses a
self ventilated (TENV/TEFC) induction motor and increased thermal protection is required for speeds below 50 % base speed, then this can be
enabled by setting
Low Speed Thermal Protection Mode
(
B44
)
= On (1).
Operation of motor I
2
t protection
Motor I
2
t protection defaults to be compatible with:
•
Forced ventilation induction motors
•
Permanent magnet servo motors
Total Output Current
(J22)
as percentage of motor
rated current
Motor speed as a
percentage of base speed
100 %
Max. permissible
continuous
current
100 %
I t protection operates in this region
2
70 %
50 %
B44
B44
= 0
= 1
Summary of Contents for E300 Series
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